In some wireless communication systems, for example, cellular communication systems such as, for example Wideband Code Division Multiple Access (WCDMA) and/or Code Division Multiple Access (CDMA) systems, a soft hand-off (SHO) mechanism may be used to transit from one servicing station to several servicing stations or from several servicing stations to a single servicing stations. For example, such a mechanism is used in commercial CDMA cellular networks such as, for example, those operating under the TIA/EIA IS-95 standard published in 1993, ITU standard IMT 2000-CDMA2000, WCDMA networks, and the like. Similar mechanisms have been developed for some Orthogonal Frequency Division Multiplexing (OFDM) systems. For example, the IEEE 802.16e WirelessMAN® standard defines a mechanism where two or more base stations may transmit the same signal to a specific user. The transmitted signals from these two or more base stations may be synchronized in time such that the delay between the received signals of the different base stations may occur within a time interval which is shorter than the cyclic prefix interval.
In an OFDM based cellular network, a receiver may perform maximal ratio combining over an equivalent channel that may contain combined channel responses from multiple base stations of the cellular network.
Unfortunately, SHO may have a number of drawbacks. Some disadvantages of SHO include increased network complexity, increased round trip delay and increased complexity of the mobile terminal.
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